1. Field of the Invention
The present invention relates to the field of electronic circuits and of microcircuits embedded in electronic devices. More specifically, the present invention relates to an electronic circuit and to a method for detecting a fault attack on this circuit.
2. Discussion of the Related Art
Embedded electronic circuits, and especially microcontroller circuits, for example, chip cards, are often attacked by malicious individuals. Among the known types of attacks, there exist non-invasive attacks, which do not destroy the chip card, and among such attacks, fault attacks. Such attacks are carried out by interrupting the power supply, generally in a sequence of short interruptions of the electronic circuit power supply. Such interruptions are performed at specific times of the circuit operation, and enable to set the circuit to a fault mode, for example, to avoid test steps.
By studying the signals on the electronic circuit responding to such attacks, malicious individuals can reconstruct the program contained in the electronic circuit and, for example, in the case of chip cards, obtain secret data stored in the card, such as cryptographic data or the PIN code of the card.
Currently, no device enables detecting fault attacks where short successive interruptions of the circuit power supply are performed. However, the detection of such attacks could be coupled to an alert or circuit blocking device so that a malicious individual can no longer use the circuit on which attacks have been performed.
There thus is a need for a circuit and a method for detecting, on an embedded electronic circuit such as a chip card, attacks where several successive short interruptions of the circuit power supply are performed.